U.S. Pat. No. 2,542,637 to De Poy is concerned with a method of rectifying a neutral salt heat-treating bath. A solid graphite or carbon rod is immersed in the bath to reduce metal oxides and scavenge for metals in solution. The rod may be periodically removed, cleansed, and replaced.
U.S. Pat. No. 4,424,145 to Sara relates to a pitch derived carbon fiber which has been boronated and intercalated with calcium. U.S. Pat. No. 4,435,375 to Tamura is directed to a graphite filament which has been formed by heating a purified graphite material in a plasma and then intercalated with an alkali metal.
U.S. Pat. No. 3,531,249 to Turkat describes pyrolytic graphite compositions which are formed by codepositing refractory metals and graphite on a mandrel to form a filament which is in essence pyrolytic graphite. U.S. Pat. No. 3,294,880 which is also to Turkat describes a continuous method of manufacturing ablative and refractory materials. The invention is particularly concerned with a method and apparatus for manufacturing ablative and refractory filaments in which hydrocarbon gases are cracked in a vacuum furnace. The decomposition products are deposited on a rotating mandrel and then continuously peeled therefrom in the form of a continuous filament. U.S. Pat. No. 3,375,308 which is likewise issued to Turkat is concerned with the making of high purity and non-melting filaments. High temperature, high strength ablative refractory materials, such as pyrolytic graphite, are produced by vapor decomposition and hydrocarbon gas cracking techniques to provide pure crystalline refractory metals, carbides, silicides and borides in free standing shapes, coatings and in compositions to form shapes and structures for space age applications.